Call it a real-life From Justin to Kelly. Or, more specifically, From Caleb to Maddie.

Monday night on American Idol’s finale, Maddie Poppe won the title — but she also announced that she had won the heart of runner-up Caleb Lee Hutchinson. The two officially came out as a couple during the live broadcast, and the audience gasped with surprised delight at the adorable news. While two other top 10 contestants, Gabby Barrett and Cade Foehner, had been open about their romance this season (at least after Ryan Seacrest outed them on Disney Night), until now, Maddie and Caleb had kept their relationship on the down-low.

“We didn’t really want people to think that we weren’t focused on the show, and also Cade and Gabby had just kind of announced that they were dating, and so we didn’t want to take away their thunder, you know,” Poppe tells Yahoo Entertainment the morning after her win, adding with a laugh, “Caleb and I kind of joked, when people would ask about us, that we were cousins!”

Poppe and Hutchinson had a couple reasons for keeping their relationship status under wraps. “We started dating around the top 24 week, and we’d noticed that there were some other couples who had gotten split up along the way,” Poppe recalls. She began to suspect that the show’s powers that be frowned upon contestants dating, and she worried that she and Hutchinson would meet a similar Romeo-and-Juliet-like fate. “I mean, it’s just my conspiracy theory, but we really didn’t want anybody to know [we were an item], because we didn’t want the producers to find out and split us up!”

The other reason for the couple’s secrecy was more competitive and strategic: “Caleb needed the women’s vote. So, we both were like, ‘He needs to appear single!’” Poppe reveals — demonstrating just how supportive the two were of each other throughout the season.

“Truly, once it got down to me and Caleb [on the finale], I really didn’t care who won,” Poppe stresses. “I mean, of course I still wanted to win, but I would have been just as happy if he had won.” When Seacrest eventually announced Poppe’s name, Hutchinson was equally thrilled. “He was so proud. He’s just super-supportive, and he was really happy for me. I mean, he’s my boyfriend, but he could have been bitter or, you know, kind of jealous. But he wasn’t any of that. He treated me like his girlfriend, not a competitor, so that was pretty cool.”

Poppe and Hutchinson started the season platonically, but they formed a bond from the start. “I met him the first day of Hollywood Week, and of all the people that day, he stood out to me the most,” Poppe recalls. “And I thought, ‘I have to get him in my group for Group Rounds!’ I found him and asked him, ‘Do you want to be in my group?’ And we hung out pretty much every day since then. We were friends at first, because we really weren’t looking to date. We weren’t looking for anything. But then, man, I don’t know, he just captured my heart. What can I say?”

From then on, they were each other’s support systems, offering each other feedback (for instance, Hutchinson and his parents encouraged Poppe to do Melanie’s “Brand New Key” during top 24 week). And they were able to separate the professional from the personal, as they both kept their eye on the Idol prize. “Caleb would say, ‘Well, do you want my advice as your boyfriend, or as your competitor?’” Poppe chuckles.

Someone else who gave the 20-year-old Iowa singer-songwriter advice throughout the season was judge Katy Perry, who made no secret that Poppe was her favorite — even boldly telling Poppe, “I’m voting for you!” on Sunday night. “That really meant a lot. That was kind of winning in itself, because I know she’s been a super-big supporter of me throughout this whole thing,” gushes Poppe. “Even when I was an underdog, she was always giving me shout-outs on Twitter. I think that actually influenced people on the fence to become my fans, just because she’s such a huge name and a pretty influential person. I don’t think it hurt. I’m sure that it helped me. And yeah, that was a really cool moment.”

Poppe says she assumed she was this season’s “underdog” partially because of Idol’s past track record, in which “WGWG” contestants like Kris Allen, Lee DeWyze, and Phillip Phillips prevailed, but their acoustic-strumming female counterparts never did. “One reason why I thought I would or could never win this is because [past contestants] like Crystal Bowersox and Brooke White were my idols when I watched the show, and they didn’t win,” she explains. “Crystal got second place, and she was my favorite. And so, I thought that’s what would happen with me, because I was so similar to them. Plus, we had powerhouses [this season] like Gabby [Barrett] and Ada [Vox], and a country voice like Caleb’s — all kinds of super-mainstream popular music and country music has such a big fanbase. I wasn’t seen as mainstream music. And so that was something that was really scary going into this. But I knew that whatever happened was supposed to happen, and even if I didn’t win, I was doing what I love.”

As Poppe prepares to release her major-label debut with the show’s new affiliated music company, Hollywood Records, she’s feeling optimistic about being able to adhere to her artistic vision — thanks to support from Hutchinson and encouragement from Perry, who actually gave Poppe an inspiring “pep talk” right after Monday’s finale. “Katy came up to me and she told me, ‘Don’t let people change you. There’s gonna be people who want you to do all kinds of different stuff. There’s gonna be people who will try to tell you what to do. You can’t let them do that. Stand your ground, and don’t give up easily.’

“But some of the biggest advice Katy’s given me, really honestly, is to just be myself — because I think that’s what got me this far. And I think it’s really cool that I didn’t have to change anything about myself to be accepted by America. I just could do exactly what I wanted, and I ended up winning. I can’t even believe that. That’s a really cool feeling.”